1. Field of Invention
The present invention is related to connectors and more particularly to a screw-joint type pneumatic tool connector.
2. Description of the Prior Art
In the use of a pneumatic equipment, a connector is commonly used to connect a tool to the air outlet pipe of a pneumatic compressor so that compressed air can be guided to drive a tool to operate.
FIG. 5 illustrates a structure of pneumatic tool connector according to the prior art, which is generally comprised of a pipe coupling 2, a socket 3, a control ring 4, a tool adapter 5, a compression spring 6, a plurality of steel balls 7, and a C-shaped retainer ring 8. The C-shaped retainer ring 8 is externally mounted on the socket 3 to retain the control ring 4 to the socket 3. The socket 3 has a plurality of round holes for the setting therein of the steel balls 7 respectively, which steel balls 7 are squeezed inside the control ring 4. The compression spring 6 is mounted on the socket 3 inside the control ring 4. The pipe coupling 2 is secured to the rear end of the socket 3 by means of screw joint. After the tool adapter 5 is coupled with a pneumatic tool, the control ring 4 must be pushed backward permitting the steel balls 7 to partly protrude beyond the round holes on the socket 3 so that the tool adapter 5 can be inserted in the socket 3. As soon as the tool adapter 5 is inserted in the socket 3, push force is immediately released from the control ring 4 permitting the compression spring 6 to push the control ring 4 to move back to original position. Therefore, the steel balls 7 are forced by the control ring 4 to respectively set in a circular groove on the outer wall of the tool adapter 5 and the tool adapter 5 becomes firmly retained to the connector. One disadvantage of this structure of pneumatic tool connector is that the tool adapter 5 can not be stably retained by the steel balls 7 and air leakage problem may happen frequently. Another disadvantage of this structure of pneumatic tool connector is that the parts of the connector are easy to wear off due to the unstable connection between the steel balls 7 and the tool adapter 5.